The most efficient way to identify mushrooms is through scientific keys like those featured in Arora's book and in several other mushroom guides (owners of the Audubon guide by Gary Lincoff can find a key to the gilled mushrooms included in the guide here). If you have never used keys before, I am sure you will be able to figure it out on your own; a key asks you to make choices, one by one, in order to narrow down possibilities. This site's keys begin with the Key to Major Groups of Mushrooms.

Unfortunately, many field guides lack keys and therefore encourage what is probably the least successful method for identifying mushrooms--namely, comparing them to photos. Photos almost never convey the many details that are important in determining a mushroom's identity, and users of field guides thus often wind up making determinations based on cap color and virtually nothing else. Color is one of the least reliable features of a mushroom! Also consider that most field guides depict and describe a few hundred mushrooms, at most--when there may be 10,000 species on the continent.

Once you have used keys to arrive at some identification possibilities, carefully compare your description of the mushroom to the descriptions in mushroom guides. The process is a lot like fingerprint analysis, in which "points" of comparison are matched by forensic scientists or, these days, software programs. The mushroom you picked in the woods, like the fingerprint lifted carefully from the crime scene, must be matched to an individual in your database (your mushroom guides), and you have maintained your objectivity by describing the mushroom in your journal before reading the descriptions.

I suppose now is not the best time to tell you that this identification process is going to fail a lot--even, perhaps, most of the time. There are several reasons for this, but suffice it to say that mushroom identification is difficult, often technical, and sometimes impossible. This is a hard nugget to swallow for those who have used field guides to identify trees or birds, for example, and expect the mushroom world to be equally easy to penetrate. One doesn't need a microscope to identify a North American tree, and plenty of field guides can be found that include more or less all the tree species native to the continent. With mushrooms, one does need a microscope, much of the time--and no one even knows how many thousands of mushroom species there are on the continent.

However, with patience you will be able to identify some mushrooms, even if you are just starting out. And as your experience develops, you will be able to identify more and more mushrooms. If you become frustrated along the way, remember this: I have watched many of the continent's most prominent living mycologists study mushrooms and throw up their hands in despair without an identification--and the ones I have not seen fail like this are the ones I have never met.